From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f71.google.com (mail-pa0-f71.google.com [209.85.220.71]) by kanga.kvack.org (Postfix) with ESMTP id DFC416B0069 for ; Thu, 8 Sep 2016 04:21:59 -0400 (EDT) Received: by mail-pa0-f71.google.com with SMTP id hi6so87735630pac.0 for ; Thu, 08 Sep 2016 01:21:59 -0700 (PDT) Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com. [148.163.156.1]) by mx.google.com with ESMTPS id zt6si45917728pab.198.2016.09.08.01.21.56 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 08 Sep 2016 01:21:57 -0700 (PDT) Received: from pps.filterd (m0098394.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.17/8.16.0.17) with SMTP id u888IeBC005576 for ; Thu, 8 Sep 2016 04:21:56 -0400 Received: from e28smtp09.in.ibm.com (e28smtp09.in.ibm.com [125.16.236.9]) by mx0a-001b2d01.pphosted.com with ESMTP id 25axf852xx-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Thu, 08 Sep 2016 04:21:56 -0400 Received: from localhost by e28smtp09.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 8 Sep 2016 13:51:53 +0530 Received: from d28relay06.in.ibm.com (d28relay06.in.ibm.com [9.184.220.150]) by d28dlp02.in.ibm.com (Postfix) with ESMTP id 06FC33940061 for ; Thu, 8 Sep 2016 13:51:51 +0530 (IST) Received: from d28av02.in.ibm.com (d28av02.in.ibm.com [9.184.220.64]) by d28relay06.in.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id u888LoDI50266346 for ; Thu, 8 Sep 2016 13:51:50 +0530 Received: from d28av02.in.ibm.com (localhost [127.0.0.1]) by d28av02.in.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id u888LmEY030162 for ; Thu, 8 Sep 2016 13:51:50 +0530 Date: Thu, 08 Sep 2016 13:51:47 +0530 From: Anshuman Khandual MIME-Version: 1.0 Subject: Re: [PATCH -v3 01/10] mm, swap: Make swap cluster size same of THP size on x86_64 References: <1473266769-2155-1-git-send-email-ying.huang@intel.com> <1473266769-2155-2-git-send-email-ying.huang@intel.com> In-Reply-To: <1473266769-2155-2-git-send-email-ying.huang@intel.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Message-Id: <57D11F9B.8060500@linux.vnet.ibm.com> Sender: owner-linux-mm@kvack.org List-ID: To: "Huang, Ying" , Andrew Morton Cc: tim.c.chen@intel.com, dave.hansen@intel.com, andi.kleen@intel.com, aaron.lu@intel.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Hugh Dickins , Shaohua Li , Minchan Kim , Rik van Riel On 09/07/2016 10:16 PM, Huang, Ying wrote: > From: Huang Ying > > In this patch, the size of the swap cluster is changed to that of the > THP (Transparent Huge Page) on x86_64 architecture (512). This is for > the THP swap support on x86_64. Where one swap cluster will be used to > hold the contents of each THP swapped out. And some information of the > swapped out THP (such as compound map count) will be recorded in the > swap_cluster_info data structure. > > For other architectures which want THP swap support, THP_SWAP_CLUSTER > need to be selected in the Kconfig file for the architecture. > > In effect, this will enlarge swap cluster size by 2 times on x86_64. > Which may make it harder to find a free cluster when the swap space > becomes fragmented. So that, this may reduce the continuous swap space > allocation and sequential write in theory. The performance test in 0day > shows no regressions caused by this. This patch needs to be split into two separate ones (1) Add THP_SWAP_CLUSTER config option (2) Enable CONFIG_THP_SWAP_CLUSTER for X86_64 The first patch should explain the proposal and the second patch should have 86_64 arch specific details, regressions etc as already been explained in the commit message. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org